Everyone, including identical twins, has a unique fingerprint.
In other words, people's identities are coded at their fingertips.
This coding system may also be compared to the barcode system
that is used today.

While it is stated in the Qur'an that it is easy for Allah to bring
man back to life after death, peoples' fingerprints are particularly
emphasized:

Yes, We are able to put together in perfect order
the very tips of his fingers. (Qur'an, 75:4)

The emphasis on fingerprints has a very special
meaning. This is because shapes and details on everyone's fingerprint
are unique to each individual. Every person who is alive or who
has ever lived in this world has a set of unique fingerprints. Furthermore,
even identical twins having the very same DNA sequence have their
own set of fingerprints.105

Fingerprints attain their final shape before birth and remain the
same for a lifetime unless a permanent scar appears. That is why
fingerprints are accepted as a very important proof of identity,
exclusive to their owner. The science of fingerprints has been used
as a non-erring identity determination method.

However, what is important is that this feature of fingerprints
was only discovered in the late 19th century. Before
then, people regarded fingerprints as ordinary curves without any
specific importance or meaning. However in the Qur'an, Allah points
to the fingertips, which did not attract anyone's attention at that
time, and calls our attention to their importance. This importance
has only been fully understood in our day.

The validity of the technique to
establish identity by means of fingerprints (AFS)
has been confirmed by various police organisations
over the last 25 years and is a legally approved method.
No technology of identity verification in our time
gives such effective results as fingerprints. Using
fingerprints to establish identity has been used in
legal processes for the last 100 years and possesses
international acceptance. “What
is a Fingerprint?,” (www.ridgesandfurrows.
homestead.com/fingerprint.html.)

In his book Fingerprint Techniques
A.A. Moenssens analyses the way that each individual
has a unique set of fingerprints:

... no two fingerprints from different
digits have ever been found to match exactly. Andre
A. Moenssens, “Is Fingerprint Identification
a ‘Science’?,” (www.forensic-evidence.com/site/
ID/ID00004_2.html#ID1.)